cpap therapy through a helmet or a full face mask in patients with acute hypoxemic respiratory failure: cross-over study

Conditions: Pneumonia, Bacterial; Respiratory Failure; COVID-19 Pneumonia

Summary: observational and randomized trials have demonstrated the high effectiveness of non-invasive helmet ventilatory support, demonstrating a reduction in intubation rate mortality compared with high-flow and standard oxygen therapy. some pilot physiological studies have shown physiological benefits of helmets compared to the oronasal mask for non-invasive ventilation. the purpose of the study is to compare markers of patient self-inflicted lung injury (p-sili), patient's comfort, work of breathing, gas exchange, and hemodynamics in patients with acute hypoxemic respiratory failure (ahrf) during non-invasive ventilation (niv) in continuous positive pressure (cpap) mode during an oronasal mask ventilation or a combination of a helmet with high-flow oxygenation as an air flow generator.

in december 2019, an outbreak of a novel coronavirus emerged in wuhan, china and rapidly spread worldwide. the world health organization (who) declared the outbreak a pandemic on march 11th, 2020. the clinical disease (covid-19) results in critical illness in about 5% of patients with predominant acute respiratory failure. observational and randomized trials have demonstrated the high effectiveness of non-invasive helmet ventilatory support, demonstrating a reduction in intubation rate mortality compared with high-flow and standard oxygen therapy. some pilot physiological studies have shown physiological benefits of helmets compared to the oronasal mask for non-invasive ventilation. the purpose of the study is to compare markers of patient self-inflicted lung injury (p-sili) (measuring esophageal pressure, transpulmonary pressure during inspiration and expiration), the patient's work of breathing (assessment of accessory muscles work) patient's comfort by visual-analog scale, gas exchange (by pao2/fio2 and respiration oxygenation index (rox-index), and hemodynamics in patients with acute hypoxemic respiratory failure (ahrf) during non-invasive pulmonary ventilation (niv) in continuous positive pressure (cpap) mode during an oronasal mask ventilation or a combination of a helmet with high-flow oxygenation as an air flow generator.

Eligibility criteria:
inclusion criteria: * patients with acute hypoxemic respiratory failure due to community-acquired pneumonia or covid-19 * the ratio of the partial pressure of oxygen in arterial blood to the inspiratory fraction of oxygen (pao2/fio2) is less than 250 mm hg while breathing atmospheric air * respiratory rate more than \> 25 per minute. * written informed consent exclusion criteria: * patients who achieve the following target parameters with only low-flow oxygen therapy (flow up to 15 l/min): spo2 \> 93%, the patient does not have a subjective feeling of fatigue, there is no visible work of the auxiliary respiratory muscles of the neck, * unstable hemodynamics (systolic blood pressure \ 5 mmol/l and/or clinically diagnosed shock) and/or life-threatening arrhythmia, * metabolic acidosis (ph \<7.30); * patients who were in the icu for less than 24 hours for any reason * primary or secondary lung diseases (exacerbation of chronic obstructive pulmonary disease (copd), bronchial asthma, interstitial lung diseases, metastatic lung disease) * cardiogenic pulmonary edema, * chronic diseases in the stag e of decompensation with the development of extrapulmonary organ dysfunction (liver cirrhosis, progression of cancer, chf), * glasgow coma scale score \<14 points, * swallowing disorders * hypercapnia (paco2\>45 mmhg), * the need for urgent tracheal intubation for any reason, * recent head surgery or anatomy that prevents the placement of a helmet or full face mask on the patient, * pregnancy, * inability to cooperate with staff